Hair Mercury Concentrations Research Articles

Reactive gaseous mercury is generated from chloralkali factories resulting in extreme concentrations of mercury in hair of workers

Occupational exposure of chloralkali workers to highly concentrated mercury (Hg) vapour has been linked to an increased risk of renal dysfunction and behavioural changes. It is generally believed that these workers are exposed to elemental Hg, which is used in abundance during the production process however, the lack in analytical techniques that would allow for identification of gaseous Hg species poses a challenge, which needs to be addressed in order to reach a consensus. Here, we present the results from simulated exposure studies, which provide sound evidence of higher adsorption rate of HgCl2 than Hg0 and its irreversible bonding on the surface of hair. We found that chloralkali workers were exposed to HgCl2, which accumulated in extremely high concentrations on the hair surface, more than 1,000 times higher than expected from unexposed subjects and was positively correlated with Hg levels in the finger- and toenails.

Children's Hair Mercury Concentrations and Seafood Consumption in Five Regions of Japan.

Exposure to methylmercury (MeHg) during the foetal and postnatal periods is known to have adverse effects on children's development. However, little attention has been paid to MeHg exposure during early childhood in Japan. To examine the regional differences in MeHg exposure and seafood consumption and the association between MeHg exposure and seafood consumption and dental metal restorations, we measured the total mercury (T-Hg) concentration in hair as an MeHg exposure index, and using questionnaires, we measured the frequency and amount of seafood consumption and the presence of dental metal restorations in 118 children aged 3-6years in five regions of Japan. The arithmetic and geometric means of the T-Hg concentrations in hair were 1.03 and 0.87ppm, respectively, and approximately 40% of the children exceeded the United States Environmental Protection Agency recommendation of 1.0ppm. Significant regional differences in the hair T-Hg concentrations were found among the five regions, and the regional differences were consistent with the traditional regional patterns of eating fatty fish. According to the regression analysis, the consumption of fatty fish, particularly tuna/swordfish, had a significant effect on hair T-Hg concentrations, whereas age, sex, the materials used for dental metal restorations, and other types of seafood or fish/shellfish had no significant effects.

Blood and hair mercury concentrations among Cree First Nations of Eeyou Istchee (Quebec, Canada): time trends, prenatal exposure and links to local fish consumption

ABSTRACTTo describe exposure to methylmercury among Cree, focusing on women of childbearing age, we used data from 2 studies. Multiple regression was employed to examine associations between blood and hair mercury concentrations and consumption of locally harvested fish.Approximately 9.9% of non-pregnant women aged 15–44 y and 3.9% of pregnant women required follow-up according to Health Canada’s blood mercury guidance value of 40 nmol/L. 8% of hair mercury observations in the non-pregnant women and 2.5% among pregnant women exceeded the equivalent threshold of 10 nmol/g. The geometric mean blood mercury concentration was 12.7 nmol/L in 1,429 persons aged 8 and over, and 17.7 nmol/L in adults aged 18 and older. The proportion of hair mercury concentrations greater than 12.5 nmol/g decreased in all age-sex groups when comparing the 2002–2009 data to published values for 1993–1994. Among women of childbearing age, local fish consumption was associated with increased blood and hair mercury concentrations.While over 90% of women of childbearing age in this population have acceptable levels of mercury, ongoing intake of mercury suggests that their consumption of fish with known high mercury content be minimised. Reducing consumption of fish known to be high in mercury content needs to be balanced with promoting ongoing connection to Cree culture and land-based activities that are also important determinants of health.

Spatial, Temporal, and Dietary Variables Associated with Elevated Mercury Exposure in Peruvian Riverine Communities Upstream and Downstream of Artisanal and Small-Scale Gold Mining.

Artisanal and small-scale gold mining (ASGM) is a primary contributor to global mercury and its rapid expansion raises concern for human exposure. Non-occupational exposure risks are presumed to be strongly tied to environmental contamination; however, the relationship between environmental and human mercury exposure, how exposure has changed over time, and risk factors beyond fish consumption are not well understood in ASGM settings. In Peruvian riverine communities (n = 12), where ASGM has increased 4–6 fold over the past decade, we provide a large-scale assessment of the connection between environmental and human mercury exposure by comparing total mercury contents in human hair (2-cm segment, n = 231) to locally caught fish tissue, analyzing temporal exposure in women of child bearing age (WCBA, 15–49 years, n = 46) over one year, and evaluating general mercury exposure risks including fish and non-fish dietary items through household surveys and linear mixed models. Calculations of an individual’s oral reference dose using the total mercury content in locally-sourced fish underestimated the observed mercury exposure for individuals in many communities. This discrepancy was particularly evident in communities upstream of ASGM, where mercury levels in river fish, water, and sediment measurements from a previous study were low, yet hair mercury was chronically elevated. Hair from 86% of individuals and 77% of children exceeded a USEPA (U.S. Environmental Protection Agency) provisional level (1.2 µg/g) that could result in child developmental impairment. Chronically elevated mercury exposure was observed in the temporal analysis in WCBA. If the most recent exposure exceeded the USEPA level, there was a 97% probability that the individual exceeded that level 8–10 months of the previous year. Frequent household consumption of some fruits (tomato, banana) and grains (quinoa) was significantly associated with 29–75% reductions in hair mercury. Collectively, these data demonstrate that communities located hundreds of kilometers from ASGM are vulnerable to chronically elevated mercury exposure. Furthermore, unexpected associations with fish mercury contents and non-fish dietary intake highlight the need for more in-depth analyses of exposure regimes to identify the most vulnerable populations and to establish potential interventions.

Mercury pollution by gold mining in a global biodiversity hotspot, the Choco biogeographic region, Colombia

Mercury (Hg) is a harmful pollutant released into the environment from gold mining activities, representing a risk to human health and the ecosystems. The aim of this study was to assess the levels of total Hg (T-Hg) in human hair, fish, sediments and air; and to determine fish consumption-based risks for T-Hg ingestion in the Choco biogeographic region, a global biodiversity hotspot located at the Colombian Pacific. Mercury concentrations in hair were measured in two locations, Quibdo, the state capital, and Paimado, a riverine community. The median T-Hg value in human hair in Quibdo was 1.26 μg/g (range: 0.02–116.40 μg/g), whereas in Paimado it was 0.67 μg/g (range: 0.07–6.47 μg/g). Mercury levels in examined locations were weakly associated with height (ρ = 0.145, P = 0.024). Air T-Hg levels in Quibdo were high inside gold shops being up to 200.9-fold greater than the background. Mercury concentrations in fish from Atrato River were above WHO limit (0.5 μg/g), with highest levels in Pseudopimelodus schultzi, Ageneiosus pardalis, Sternopygus aequilabiatus, Rhamdia quelen and Hoplias malabaricus, whereas the lowest appeared in Cyphocharax magdalenae and Hemiancistrus wilsoni. Based on fish consumption, these last two species offer low risk to human health. Sediment samples from fifty different sites of Atrato River showed low T-Hg concentrations, with little variability between stations. However, contamination factors revealed a moderate pollution in 44% of sampling sites along the river. In conclusion, Hg pollution is widespread in the Biogeographic Choco and governmental actions must be taken to protect the population and preserve its biodiversity.

Correlations between hair and tissue mercury concentrations in Icelandic arctic foxes (Vulpes lagopus)

Monitoring organic pollutants in wildlife is a common approach to evaluate environmental health, chemical exposure and to make hazard assessments. However, pollutant concentrations measured from different tissue types among studies impede direct comparisons of levels and toxicity benchmarks among species and regions. For example, mercury (Hg) is a metal of both natural and anthropogenic origin which poses health risks for marine and arctic biota in particular. Although hair is recognized as the least invasive sample type for Hg exposure measurement in wildlife, measurements in previous studies have used different tissues among individuals and species. This lack of tissue type consistency hinders cross study comparisons. Therefore to systematically evaluate the use of hair in ecotoxicological studies, total mercury (THg) concentrations measured from hair were compared to values obtained from liver and kidney in 35 Icelandic arctic foxes (Vulpes lagopus). THg concentrations varied considerably among tissues with hair and kidney levels generally lower than in liver. Nevertheless, significant correlations among tissue types were observed. THg values in hair were predictive for liver (R2=0.61) and kidney THg levels (R2=0.51) and liver values were a good predictor of THg in kidney (R2=0.77). We provide further evidence that non-invasively collected hair samples reflect the THg levels of internal tissues. We present equations derived from multiple linear regression models that can be used to relate THg levels among tissue types in order to extrapolate THg values from hair to soft tissues. Using these equations, we compare the results of previous studies monitoring THg levels in different tissues of arctic foxes from various regions of the Arctic. Our findings support that hair is a suitable sample matrix for ecotoxicological studies of arctic predators and may be applied in both wildlife welfare and conservation contexts for arctic vulpine species.

Hair mercury and risk assessment for consumption of contaminated seafood in residents from the coast of the Persian Gulf, Iran

The health risks of mercury exposure due to the high consumption of aquatic were assessed for fishermen and non-fishermen families living on the Bandar Abbas, Bushehr, and Mahshahr cities located in the coast of Persian Gulf (Iran). The mean hair mercury concentration of people in Bandar Abbas, Bushehr, and Mahshahr cities was obtained 1.56±0.17, 1.97±0.22, and 5.12±0.3μgg-1, respectively. Hair mercury concentration in 8.8% of people exceeded the no observed adverse effects level (NOAEL) of 10μgg-1 declared by the World Health Organization (WHO). The fish and shrimps consumption, place of living, and fisher and non-fisherman family were variables that significantly effected on mercury levels in the hair. The effect of other factors (age, sex, and number of dental amalgam fillings) on hair mercury was not significant. The mean concentrations of mercury in three fish species in Mahshahr exceeded the recommended maximum standard level (0.5μgg-1) set by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA). The estimated weekly intake (EWI) for mercury in some fish species in Bandar Abbas, Bushehr, and Mahshahr was higher than the provisional tolerable weekly intake (1.6μgkg-1 bw) set by European Food Safety Authority (EFSA) for some groups. The significant positive correlation between daily mercury intake and hair mercury concentration of people (r=0.64, P<0.001) reasserts that the hair mercury concentration could be explained by fish consumption. HQ>1 was obtained for women in child bearing age in fishermen families in Bandar Abbas and Bushehr cities, children in fishermen families in Bushehr, and for all groups of population except adult in non-fishermen families in Mahshahr. So, the limited consumption of some fish species for these groups of people is recommended. The maximum of allowable fish consumption rate was 0.70 meals/month for Pseudorhombus arsius from Mahshahr fish for women of child bearing age. Also, it is necessary to create and monitor and enforce environmental standards, preventing the entry of pollutants released into the marine aquatic environment without proper early treatment.

Determination of Mercury Daily Intake and Hair-to-Blood Mercury Concentration Ratio in People Resident of the Coast of the Persian Gulf, Iran.

The objectives of this study were to understand the mercury daily intake and hair-to-blood mercury ratio in fishermen and non-fishermen families in the coast of the Persian Gulf in Iran. The mean mercury concentration in the hair of fishermen and non-fishermen families was 5.76 and 2.27μg/g, respectively. The mean mercury concentrations of RBCs were obtained for fishermen families and non-fishermen families: 35.96 and 17.18μg/L, respectively. Hair mercury concentrations in 17% of people were higher than 10μg/g, the No Observed Adverse Effects Level set by the World Health Organization. 78% of people had a blood mercury value >5.8μg/L, the standard level set by the U.S. Environmental Protection Agency. A significant correlation (r=0.94, p=0.000) was seen between log hair and RBCs mercury concentrations. The mean mercury daily intake for fishermen and non-fishermen families was 0.42 and 0.20µg/kg BW per day, respectively. The mean mercury daily intake of fishermen families was higher than the provisional tolerable daily intake (0.23µg/kg BW per day) suggested by the Joint Expert Committee on Food Additives. Mercury daily intake significantly correlated with fish consumption (r=0.50, p=0.000) and log hair mercury (r=0.88, p=0.000). The total mean of hair-to-blood mercury concentration ratio was 306. We conclude that the use of mercury concentrations in the hair and RBCs could have been suitable biomarkers for predicting mercury exposure of people with a high rate of fish consumption.

Hair Mercury Level is Associated with Anemia and Micronutrient Status in Children Living Near Artisanal and Small-Scale Gold Mining in the Peruvian Amazon.

Anemia has been widely studied in global health contexts because of severe nutritional deficiency, and more recently, inflammatory status, but chemical exposures are rarely considered. Until recently, "anemia" was used synonymously with "iron deficiency anemia (IDA)" in global health settings. However, only 50% of anemia cases worldwide are IDA. Environmental toxicology studies of anemia risk have generally focused on populations in developed countries, albeit with high exposure to environmental toxicants, such as lead or cadmium. In the developing world, toxicant exposures commonly coexist with other risk factors for anemia. In particular, artisanal and small-scale gold mining (ASGM) communities are at risk for dietary methylmercury exposure through contaminated fish consumption, and for anemia due to food insecurity and infectious and chronic diseases. Here, we report analysis of total hair mercury content, hemoglobin, and serum micronutrient levels in children < 12 years of age (N = 83) near ASGM in the Peruvian Amazon. Forty-nine percent (N = 29/59) of those aged < 5 years were anemic (< 11 g/dL) and 52% (N = 12/23) of those aged 5-11 years (< 11.5 g/dL). Few children were stunted, wasted, or micronutrient deficient. Median total hair mercury was 1.18 μg/g (range: 0.06-9.70 μg/g). We found an inverse association between total mercury and hemoglobin (β = -0.12 g/dL, P = 0.06) that persisted (β = -0.14 g/dL, P = 0.04) after adjusting for age, sex, anthropometrics, and vitamin B12 in multivariate regression. This study provides preliminary evidence that methylmercury exposure is associated with anemia, which is especially relevant to children living near ASGM.

Gestational diabetes and offspring birth size at elevated environmental pollutant exposures

BackgroundGestational diabetes mellitus (GDM) is associated with increased availability of glucose and macronutrients in fetal circulation and macrosomia. Therefore, the role of GDM in the association between metabolism-disrupting chemicals and birth size deserves attention. ObjectiveWe examined whether GDM may mediate or modify the associations between maternal environmental pollutant exposures and offspring birth size measures. MethodsWe analyzed 604 Faroese pregnant women and their offsprings born in 1997–2000. Maternal pregnancy serum concentrations of organochlorine compounds (OCs: polychlorinated biphenyl (PCB) congeners and dichlorodiphenyldichloroethylene (DDE)), and five perfluoroalkyl substances (PFASs), and hair and cord blood mercury concentrations were measured. We used regression (single-pollutants) and structural equation models (SEMs) (multiple-pollutant analyses using latent constructs of OCs, PFASs and mercury) to estimate the associations with GDM and birth size measures, accounting for mediation and/or effect modification by GDM. ResultsSerum-DDE and hair-mercury concentrations were associated with GDM (adjusted OR per concentration doubling: 1.29; 95% CI: 0.94, 1.77 for DDE, and 0.79; 95% CI: 0.62, 0.99 for mercury), but in multiple pollutant-adjusted SEMs only a positive association between OC exposure and GDM remained significant (change in GDM odds per OC doubling: 0.45; 95% CI: 0.05, 0.86). PCB and overall OC exposure were positively associated with head circumference (SEM; mean change per OC doubling: 0.13cm; 95% CI, 0.01. 0.25). Overall PFAS exposure was inversely associated with birth weight (SEM; mean change per PFAS doubling: −169g; 95% CI: −359, 21), and for many single-PFASs we found a pattern of inverse associations with birth weight and head circumference in boys, and positive or null associations in girls. None of the environmental pollutants was associated with offspring length. GDM neither modified nor mediated the associations with birth size measures. ConclusionsWe found associations with GDM and offspring birth size to be specific to the environmental pollutant or pollutant group. Associations with birth size measures appear to be independent of GDM occurrence.

Changes in Hair Mercury Levels Among Women of Child-Bearing Age Following an Educational Intervention.

Describe mercury exposures among women of childbearing age before and after an educational intervention. Women age 18 to 45 were recruited to participate in an educational intervention concerning fish consumption. Fish consumption habits and total mercury concentration in hair were assessed pre- and post-intervention. Regression models examined associations between mercury, fish consumption, and demographics. Overall, 234 women completed the study. On average, mercury concentrations increased by 0.01 ppm (parts per million) following the intervention, despite declines in fish consumption; however, women in the 90th percentile for mercury at baseline decreased concentrations significantly while maintaining high rates of fish consumption. Mercury concentrations were positively correlated with fish consumption and certain demographic characteristics. The intervention reached individuals most at-risk. Healthcare providers should discuss fish consumption habits with women to encourage consumption of low-risk fish, and identify women needing education and counseling.

Public health benefits of hair-mercury analysis and dietary advice in lowering methylmercury exposure in pregnant women.

To evaluate whether a public health intervention using focused dietary advice combined with a hair-mercury analysis can lower neurotoxic methylmercury exposure among pregnant women without decreasing their overall intake of seafood. A total of 146 pregnant women were consecutively recruited from the antenatal clinic at a Danish university hospital at their initial ultrasound scan. Dietary advice was provided on avoiding methylmercury exposure from large predatory fish and a hair sample from each participant was analysed for mercury, with the results being communicated shortly thereafter to the women. A dietary questionnaire was filled in. Follow-up three months later included a dietary questionnaire and a repeat hair-mercury analysis. In the follow-up group, 22% of the women had hair-mercury concentrations above a safe limit of 0.58 µg/g at enrolment, decreasing to 8% three months later. Average hair-mercury concentrations decreased by 21%. However, the total seafood intake remained at the same level after three months. Increased exposure to methylmercury among pregnant women is an important public health concern in Denmark. The observed lowering of hair-mercury concentrations associated with dietary advice corresponds to a substantial public health benefit that probably makes such an intervention highly profitable.

Methylmercury exposure and cognitive abilities and behavior at 10 years of age

BackgroundMethylmercury (MeHg) is a known developmental neurotoxicant present in fish, yet the impact of childhood exposure is uncertain, especially in children with poor nutrition. ObjectivesTo evaluate associations of MeHg exposure with cognitive abilities and behavior in children from a poor rural area in Bangladesh. MethodsThe MeHg exposure was assessed in 1434 ten-year-old children by measuring mercury concentrations in hair (hair-Hg), using inductively coupled plasma mass spectrometry. Cognitive abilities were assessed with the Wechsler Intelligence Scale for Children (4th edition), and behavior by the parent-report Strengths and Difficulties Questionnaire. ResultsChildren's median hair-Hg was 674μg/kg (range 70–17,561μg/kg). Concentrations did not differ by distance from scalp, indicating a similar exposure over time. No multivariable-adjusted associations were observed between the children's hair-Hg and their cognitive abilities. However, children in the highest tertile of hair-Hg had a lower prevalence of hyperactivity (OR: 0.61, 95% CI: 0.45–0.83) and peer relationship problems (OR: 0.58, 95% CI: 0.44–0.76), compared to children in the lowest tertile. The corresponding ORs were slightly stronger in children from families with lower socioeconomic status (OR: 0.56, 95% CI: 0.34–0.90 and OR: 0.48, 95% CI: 0.30–0.74) than in children from families with higher socioeconomic status (OR: 0.73, 95% CI: 0.49–1.08 and OR: 0.72, 95% CI: 0.51–1.02). Similar stronger ORs were observed in underweight children. ConclusionMeHg exposure was not associated with cognitive function, but inversely associated with certain adverse behavior. More studies are needed concerning the risk-benefit of different fish consumption in rural Bangladesh.

Assessment of Occupational Exposure to Mercury Concentrations in Hair and Nail of Dental Staff at Some Dental Clinics in Makkah Region

Studies showed that dentists and dental staff working with amalgam are chronically exposed to mercury that accumulates in their bodies in higher levels than those individuals not occupational exposed to mercury. Mercury levels in dental staff averaged at least 2 times that of control subjects in hair, nails, urine and blood. This study aimed to review long-standing mercury monitoring concentration in dental staff hair and nail in Makkah Saudi Arabia. 139 hair and nail samples were collected among male and female with average age ≥30 years. 83 samples were collected from dental staff working at different polyclinics and private clinics in Makkah region while 56 samples were collected from volunteers as control sample. Hair and nail samples were analysed using a Perkin Elmer (ICP-MS 7300). The study showed that in dental staff both males and females the mercury concentration in hair increased with age up to mid-30s, then gradually decrease. Moreover, the study found that mean hair mercury levels in both males and females were highest in individuals had preference of fish consumption ≥4.46 μg/l, followed by dental staff had a higher supplementation intake. While the nail mercury concentrations in both males and females were also higher in those individuals with high fish consumption (≥3.08 μg/l). The study approved a significant correlation between mercury levels in dental staff hair and nail, although conclusive evidence is lacking that directly correlates amalgam with adverse health effects, dental staff should remain knowledgeable about mercury release from amalgam through direct exposure.

Chemical Forms of Mercury in Human Hair Reveal Sources of Exposure.

Humans are contaminated by mercury in different forms from different sources. In practice, contamination by methylmercury from fish consumption is assessed by measuring hair mercury concentration, whereas exposure to elemental and inorganic mercury from other sources is tested by analysis of blood or urine. Here, we show that diverse sources of hair mercury at concentrations as low as 0.5 ppm can be individually identified by specific coordination to C, N, and S ligands with high energy-resolution X-ray absorption spectroscopy. Methylmercury from seafood, ethylmercury used as a bactericide, inorganic mercury from dental amalgams, and exogenously derived atmospheric mercury bind in distinctive intermolecular configurations to hair proteins, as supported by molecular modeling. A mercury spike located by X-ray nanofluorescence on one hair strand could even be dated to removal of a single dental amalgam. Chemical forms of other known or putative toxic metals in human tissues could be identified by this approach with potential broader applications to forensic, energy, and materials science.

Economic implications of mercury exposure in the context of the global mercury treaty: Hair mercury levels and estimated lost economic productivity in selected developing countries

Several developing countries have limited or no information about exposures near anthropogenic mercury sources and no studies have quantified costs of mercury pollution or economic benefits to mercury pollution prevention in these countries. In this study, we present data on mercury concentrations in human hair from subpopulations in developing countries most likely to benefit from the implementation of the Minamata Convention on Mercury. These data are then used to estimate economic costs of mercury exposure in these communities. Hair samples were collected from sites located in 15 countries. We used a linear dose-response relationship that previously identified a 0.18 IQ point decrement per part per million (ppm) increase in hair mercury, and modeled a base case scenario assuming a reference level of 1 ppm, and a second scenario assuming no reference level. We then estimated the corresponding increases in intellectual disability and lost Disability-Adjusted Life Years (DALY). A total of 236 participants provided hair samples for analysis, with an estimated population at risk of mercury exposure near the 15 sites of 11,302,582. Average mercury levels were in the range of 0.48 ppm–4.60 ppm, and 61% of all participants had hair mercury concentrations greater than 1 ppm, the level that approximately corresponds to the USA EPA reference dose. An additional 1310 cases of intellectual disability attributable to mercury exposure were identified annually (4110 assuming no reference level), resulting in 16,501 lost DALYs (51,809 assuming no reference level). A total of $77.4 million in lost economic productivity was estimated assuming a 1 ppm reference level and $130 million if no reference level was used. We conclude that significant mercury exposures occur in developing and transition country communities near sources named in the Minamata Convention, and our estimates suggest that a large economic burden could be avoided by timely implementation of measures to prevent mercury exposures.

Hair toxic and essential trace elements in children with autism spectrum disorder

The objective of the study was to investigate hair trace elements content in children suffering from autism spectrum disorder (ASD). A total of 74 ASD children and 74 sex- and age-matched controls divided into two age groups (2-4 and 5-9years) were investigated. Hair trace elements content was assessed using inductively coupled plasma mass spectrometry. A general cohort of ASD children was characterized by 29%, 41%, and 24% lower hair levels of chromium (Cr), iodine (I), and vanadium (V), respectively, whereas the level of selenium (Se) exceeded the respective control values by 31%. In ASD children aged 2-4years hair Cr, I and V content was 68%, 36% and 41% lower than in the controls. Older ASD children were characterized by 45% increase in hair Se levels. In a general cohort of ASD children hair beryllium (Be) and tin (Sn) levels were 50% and 34% lower than the control values. In the first age group (2-4years) of ASD children 34%, 42%, and 73% lower levels of arsenic (As), boron (B), and Be were detected. In the second age group of ASD children only a nearly significant 25% decrease in hair lead (Pb) was detected. Surprisingly, no significant group difference in hair mercury (Hg), zinc (Zn), and copper (Cu) content was detected. Generally, the results of the present study demonstrate that children with ASD are characterized by lower values in hair of not only essential but also toxic trace elements.

Mercury Human Exposure in Populations Living Around Lake Tana (Ethiopia).

A survey carried out in Lake Tana in 2015 found that Hg levels in some fish species exceeded internationally accepted safe levels for fish consumption. The current study assesses human exposure to Hg through fish consumption around the Lake Tana. Of particular interest was that a dietary intake of fishes is currently a health risk for Bihar Dar residents and anglers. Hair samples were collected from three different groups: anglers, college students and teachers, and daily laborers. A questionary includes gender, age, weight, activity. Frequency of fish consumption and origin of the eaten fish were completed by each participant. Mercury concentrations in hair were significantly higher (P value <0.05) for anglers (mean ± standard deviation 0.120 ± 0.199μg/g) than college students (mean ± standard deviation 0.018 ± 0.039μg/g) or daily workers (mean ± standard deviation 16 ± 9.5ng/g). Anglers consumed fish more often than daily workers and college group. Moreover, there was also a strong correlation (P value <0.05) between the logarithms of total mercury and age associated with mercury concentration in scalp hair. Mercury concentrations in the hair of men were on average twice the value of the women. Also, users of skin lightening soap on a daily basis had 2.5 times greater mercury in scalp hair than non-users. Despite the different sources of mercury exposure mentioned above, the mercury concentrations of the scalp hair of participants of this study were below levels deemed to pose a threat to health.

Hair Mercury Concentrations in Western Hudson Bay Polar Bear Family Groups.

Methylmercury is one of the more toxic forms of mercury (Hg), the biomagnification of which is prevalent in the Arctic where apex predators such as polar bears (Ursus maritimus) can carry high loads. The maternal transfer of contaminants to offspring is a concern, as offspring may be particularly sensitive to the effects of environmental pollutants during early development. However, few studies of polar bears report on Hg in dependent young. We examined hair total Hg (THg) concentrations in 24 polar bear family groups in western Hudson Bay: mother, cub-of-the-year (COY), yearling, and 2 year old. THg concentrations increased with bear age, with COYs having lower concentrations than other offspring groups (p ≤ 0.008). Using AICc-based regression models, we found maternal THg to be positively related to body condition and litter size, while overall offspring THg was positively related to maternal body condition in addition to being dependent on the sex and age of the offspring. COY THg concentrations were positively related to maternal THg while also depending on the sex of the offspring. Considering our results, future studies in polar bear ecotoxicology are encouraged to include offspring of different ages and sexes.

Hair mercury concentrations in residents of Sundarban and Calcutta, India

Few studies on hair mercury have been conducted in India despite the fact that India is the world's third largest producer of coal and coal is India's primary energy source. No studies have been conducted in the Indian state of West Bengal which has a coastline with the Bay of Bengal. This study examined the concentration of mercury in hair in two diverse populations in West Bengal, India: Sundarban, a mangrove wetland where fishing is a common occupation, and Calcutta, a megacity and India's oldest functioning port. Individuals from whom scalp hair was collected (N=100) were asked a series of questions on occupation, education, age, smoking and alcohol consumption, and fish consumption. SAS was utilized to generate descriptive statistics including frequency and univariate analyses and to perform regression analyses to determine significant predictors of hair mercury in this population. The mean hair mercury increased across the first three age categories (<21, 21–30, 31–45) and decreased in the fourth category (>45). Hair mercury concentration was significantly higher among residents of Sundarban compared to Calcutta (p=0.0005). In multivariable analysis, location (Sundarban vs. Calcutta) and age were significant predictors of hair mercury concentration (p=0.0120 and p=0.0161, respectively). Average hair mercury concentrations in this study were not particularly elevated. Smoking and alcohol consumption were predictors of hair mercury concentration. The hair mercury in Sundarban residents compared to Calcutta residents may be elevated due to greater consumption of fish and type of fish consumed.